1. Field of the Invention
This invention is directed to acoustic towed arrays and more specifically to a sensor alignment device for accurate positioning of magnetic heading sensor modules in towed line arrays.
2. Statement of the Prior Act
Towed line arrays are used extensively in submarines, surface ships and oil exploration for detection purposes. A towed acoustic line array includes a liquid-filled hose containing a linear array of hydrophones for sound detection and magnetic heading sensors. These hydrophones and magnetic heading sensor are distributed inside the hose in a predetermined configuration together with their associated electronics including their power Sources. These sensors are of different types depending upon the requirements put upon the towed line arrays. The towed line arrays form an acoustic beam pattern which is used for the detection of targets in the area under surveillance. Additionally, it is important to determine accurately the position of the acoustic sensors and the towed line array as a function of time. A series of magnetic heading sensors distributed along the length of the towed line array are used for that purpose. It is desirable to have relatively small magnetic heading sensors for accurate position determination. A towed line array is formed from a long cable using various interconnecting acoustic sensors and magnetic heading sensors tied together. A mechanically rugged KEVLAR sheet or web is wrapped around the various elements, which is then placed inside a liquid filled hose. It is imperative to keep the magnetic heading sensors aligned within the hose and symmetrical with respect to the line passing through the center of the hose. Any misalignment of the magnetic heading sensors gives erroneous results. It is thus desirable to have a simple device which will maintain the positions of the magnetic heading sensors symmetrical with respect to the central axial line passing through the hose of the towed line array.